1. Field of the Invention
This invention relates generally to wireless telecommunication. More particularly, it relates to the delivery of location information to PSAP/ALI systems in a non-landline environment i.e. cellular, VoIP etc in an emergency services call flow.
2. Background of Related Art
9-1-1 is a phone number widely recognized in North America as an emergency phone number that is used to contact emergency dispatch personnel. Enhanced 9-1-1 (E9-1-1) is defined by the transmission of callback number and location information when 9-1-1 is used. E9-1-1 may be implemented for landline, cellular or VoIP networks. A Public Service Answering Point (PSAP) is a dispatch office that receives 9-1-1 calls from the public. A PSAP may be a local, fire or police department, an ambulance service or a regional office covering all services.
Regardless of the network type, a 9-1-1 service becomes E-9-1-1 when automatic number identification and automatic location information related to the call is provided to the 9-1-1 operator at the PSAP. A primary challenge results from the fact that calls may arrive at the PSAP without callback number or location information displayed at the emergency operators terminal.
A PSAP is connected to one Automatic Location Identifier (ALI). An ALI is a database that accepts a PSAP query with telephone number, relates the telephone number to an address and provides that address (location information) back to the PSAP in a manner that works for the customer premise equipment (CPE) display. An ALI is typically owned by a LEC or a PSAP, and may be regional (i.e. connected to many PSAPs) or standalone (i.e. connected to only one PSAP). There is no one single standard interface protocol for PSAP-ALI connection/communication.
Most PSAPs are publicly funded and maintain only one outside ALI connection for both landline and non-landline networks. Some ALIs are able to support only one outside connection to a positioning center. This is problematic for non-landline networks, which have users who are inherently mobile and may be in a particular PSAP-ALI jurisdiction, but their provider does not maintain a connection to the PSAP/ALI.
FIG. 7 shows a conventional landline public safety access point (PSAP) to automatic location identifier (ALI) connection.
In particular, upon receiving a 9-1-1 call, the PSAP queries their ALI for location data. As shown in FIG. 7 in landline telephony, an ALI 401 accepts a PSAP 400 query for location and returns location based on pre-provisioned data for the telephone number.
FIG. 8 shows a context diagram for a conventional non-landline XPC network.
In particular, as shown in FIG. 8 in non-landline telephony, PSAPs 400a, 400b query the same ALI 401a, 401b for location information. However, the ALI 401a, 401b is not pre-provisioned with location data for non-landline calls (e.g. cellular, VoIP etc) and must communicate with other network entities to obtain and deliver location data to the PSAP 400a, 400b. 
Non-landline telephony standards (e.g. cellular, VoIP etc) have mandated that ALIs 401, 401a, 401b maintain connectivity to positioning centers 402a, 402b, 402c that are able to provide current location data for a non-landline call. In the current state of technology the positioning center 402 provides the caller's location and the callback number to the ALI, which passes it to the requesting PSAP. As can be seen in FIG. 8, an ALI may maintain connectivity to more than one positioning center via an multiple interface types 403a, 403b, 403c, . . . , etc.—both standard and non-standard (e.g. NENA ESP, PAM, E2+etc).
As used herein, the generic term “XPC” refers interchangeably to any standards-based positioning center.
A positioning center 402 may be any one of the following types used in non-landline networks:                GMLC (Gateway Mobile Location Center): The positioning center that retrieves, forwards, stores and controls emergency position data within the GSM location network.        MPC (Mobile Position Center): The positioning center that retrieves, forwards, stores and controls emergency position data within the ANSI location network.        VPC (VoIP Positioning Center): The positioning center which retrieves, forwards, stores and controls emergency position data within the VoIP location network.        
The term “XPC network” is used herein when appropriate to refer to any non-landline network where a positioning center 402 responds to ALI 401a, 401b queries for location i.e. cellular, VoIP etc.
The term “PSAP” refers herein to either a public safety access point (PSAP), or to an Emergency Call Center (ECC), a VoIP term.
There is no uniformity among the thousands of different PSAPs with regard to how they request location data delivery (e.g. there are many different protocol interfaces), or as to how that data displayed on the PSAP customer premise equipment (CPE) varies, because the technology for connecting calls varies between the many manufacturers of, and carriers using, ALI devices. Moreover, some PSAPs are not enhanced, and thus do not receive the callback or location information at all from any phone, be it landline, cellular or VoIP.
Multiple implementations of ALI-XPC interface types are possible. Conventional ALI networks are overly complex because ALI networks nationwide must support multiple and varied ALI-XPC interfaces with different configurations.
Each carrier selects a single XPC to provide location data for its callers—not all XPCs have connectivity with all the ESME/ALI servers associated with the corresponding PSAPs that may be requesting location. Conventional XPCs for a non-landline service provider are required to handle many aspects in the emergency services call flow—from routing an emergency E9-1-1 call to the relevant PSAP; to providing ALI information to the PSAP. This creates a highly complex architecture.
There is a need for an architecture and methodology that both simplifies the complexity of the national PSAP and/or ALI network, and which also increases system efficiencies by reducing required system elements.